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if DNA can encode everything the brain does with N bits of information, then regardless of how the DNA behaves, we have at least a loose estimate of the level o
by demallien 16y ago
if DNA can encode everything the brain does with N bits of information, then regardless of how the DNA behaves, we have at least a loose estimate of the level of complexity in the brain.
No even close. Imagine a kilobyte filled with alternating zeros and ones. We have two commonly used methods for describing the information content of this kilobyte. Shannon information content is closely approximated by today's compressors - and 1k worth of alternating zeros and ones compresses to next to nothing. Kogorov Complexity is the length of the minimum necessary program to produce the 1k worth of zeros - again, a simple loop, incrementing a pointer then dereferencing the pointer to fill the address with alternately a zero or a one suffices - a mere handful of bytes are necessary.
Now imagine that the RAM chip holding the zeros and ones is hit by a bunch of cosmic rays , flipping about 10% of the bits. Both the size of a compressed version of the new kilobyte, and the Kogorov program to generate the new sequence are both going to dramatically increase in size.
Now, the thing is that DNA produces a brain to a fairly homogenous pattern - it's the equivalent of my series of alternating zeros and ones, although admittedly it's a bit more complex than that - this is to be expected, there's more Shannon information in DNA for encoding a brain than there was in my simple pattern of zeros and ones.
The cosmic rays are the equivalent of a brain learning, encoding information by weighting connections between neurons. This process massively increases the amount of information stored in a human brain, but this information must be copied if you actually want the copy to behave like the original. I would expect this amount of information to be several orders of magnitude bigger than that found in the DNA, which is why Kurzweil's claim is just completely off the wall.
- ewjordan 16y agoWe're arguing different things. You're talking about the information content required to reproduce a particular brain, which I agree, has a massive Kolmogorov complexity (even if we decide, as we might want to, to factor out many equivalence classes based on behavior). Far more than a DNA estimate would hint at. But I'm just talking about (as are most AI people, and I think Kurzweil, as well) the informational content required to build a brain. Any old brain, could be yours, could be mine, is probably neither. The information required to do this is much lower, and corresponds loosely to your first example, a kilobyte with alternating ones and zeros.